Thermodynamic equilibrium conditions of graphene films on SiC

First-principles surface phase diagrams reveal that epitaxial monolayer graphene films on the Si side of 3C-SiC(111) can exist as thermodynamically stable phases in a narrow range of experimentally controllable conditions, defining a path to the highest-quality graphene films. Our calculations are based on a van der Waals corrected density functional. The full, experimentally observed (6 sqrt(3)x 6 sqrt(3))-R30 supercells for zero- to trilayer graphene are essential to describe the correct interface geometries and the relative stability of surface phases and possible defects

Exclusive dealing and vertical integration in interlocking relationships

We develop a model of interlocking bilateral relationships between upstream firms (manufacturers)that produce differentiated goods and downstream firms (retailers) that compete imperfectly for consumers. Contract offers and acceptance decisions are private information to the contracting parties. We show that both exclusive dealing and vertical integration between a manufacturer and a retailer lead to vertical foreclosure, to the detriment of consumers and society. Finally, we show that firms have indeed an incentive to sign such contracts or to integrate vertically

Length Dependence of Ionization Potentials of Trans-Acetylenes: Internally-Consistent DFT/GW Approach

We follow the evolution of the Ionization Potential (IP) for the paradigmatic quasi-one-dimensional trans-acetylene family of conjugated molecules, from short to long oligomers and to the infinite polymer trans-poly-acetylene (TPA). Our results for short oligomers are very close to experimental available data. We find that the IP varies with oligomer length and converges to the given value for TPA with a smooth, coupled inverse-length-exponential behavior. Our prediction is based on an "internally-consistent" scheme to adjust the exchange mixing parameter $\alpha$ of the PBEh hybrid density functional, so as to obtain a description of the electronic structure consistent with the quasiparticle approximation for the IP. This is achieved by demanding that the corresponding quasiparticle correction, in the GW@PBEh approximation, vanishes for the IP when evaluated at PBEh($\alpha^{ic}$). We find that $\alpha^{ic}$ is also system-dependent and converges with increasing oligomer length, allowing to capture the dependence of IP and other electronic properties.Comment: 22 pages with 9 figures, submitted to Physical Review

The Development of an E-Participation Platform for Rural Areas in the Study Area of Niedernhall

The participation methods changed in recent years with the evolution of communication methods in general. It goes from an analog approach to a more information technology-based concept. This new form of participation is called e-Participation. With this new form of participation, the process opens up for different new technologies.The emergence of 3D Web-visualisation technologies presents themselves as an interesting application in the participation field. Especially regarding planning participation. Different examples introduce this concept in big cities andare based on open 3D city model data.However, there is also a need for this participation concept in a smaller urban area. This paper shows a way to provide an easy to access 3D model of areas in Baden-Württemberg for participation processes. In this paper, the system was tested with a trial run in a small village where the parish council was asked to design a public place. The platform provided them with functionalities to design in the 3D environment on the web globe. These functionalities were introduced to the council at an on-site appointment. This proves the technical validity of the project. The usability and acceptance of this method by the council will be determined by a questionnaire at a later stage in the project